Lamellar particles with functional coating

ABSTRACT

There is disclosed a functional lamellar particle including an unconverted portion of the lamellar particle, wherein the unconverted portion includes a first metal, a converted portion of the lamellar particle disposed external to a surface of the unconverted portion, wherein the converted portion includes a chemical compound of the first metal; and a functional coating disposed external to a surface of the converted portion.

RELATED APPLICATION

This application claims priority to U.S. Provisional Application No.62/465,605, filed Mar. 1, 2017, the disclosure of which is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

This application generally relates to metal chemical conversion pigmentswith a functional coating. Methods of making the pigments are alsodisclosed.

BACKGROUND

Current methods of producing pigments are expensive, require largecapital investments, and/or yield pigment that requires additionalpassivation and/or compatibilization processes. Thus, there exists aneed for a lower cost method of manufacturing pigments that does notrequire additional passivation and compatibilization processes.

SUMMARY

Aspects of the present disclosure relate to, among other things, afunctional lamellar particle including an unconverted portion of thefunctional lamellar particle, wherein the unconverted portion includes afirst metal; a converted portion of the functional lamellar particledisposed external to a surface of the unconverted portion, wherein theconverted portion includes a chemical compound of the first metal; and afunctional coating disposed external to a surface of the convertedportion.

It can be understood that both the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive of the disclosure, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of thepresent disclosure and together with the description, serve to explainthe principles of the disclosure.

FIG. 1 is a pre-conversion lamellar particle according to an aspect ofthe disclosure;

FIG. 2 is a converted lamellar particle according to an aspect of thedisclosure;

FIG. 3 is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 4 is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 5 is a pre-conversion lamellar particle according to another aspectof the disclosure;

FIG. 6 is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 7 is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 8 is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 9 is a pre-conversion lamellar particle according to another aspectof the disclosure;

FIG. 10A is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 10B is another converted lamellar particle according to anotheraspect of the disclosure;

FIG. 11A is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 11B is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 12A is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 12B is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 13 is a pre-conversion lamellar particle according to anotheraspect of the disclosure;

FIG. 14 is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 15 is a pre-conversion lamellar particle according to anotheraspect of the disclosure;

FIG. 16A is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 16B is a converted lamellar particle according to another aspect ofthe disclosure;

FIG. 17 is a photograph of a pre-conversion lamellar particle and aconverted lamellar particle according to aspects of the disclosure;

FIG. 18 is a graph of the visible spectrum of lamellar particlesaccording to various aspects of the disclosure;

FIG. 19 is a graph of the infrared spectrum of lamellar particlesaccording to various aspects of the disclosure;

FIG. 20 is a graph of the visible spectrum of lamellar particlesaccording to various aspects of the disclosure;

FIG. 21 is a graph of the infrared spectrum of lamellar particlesaccording to various aspects of the disclosure;

FIG. 22 is functional converted lamellar particle according to an aspectof the disclosure;

FIG. 23 is a functional converted lamellar particle according to anotheraspect of the disclosure; and

FIG. 24 is a functional converted lamellar particle according to anotheraspect of the disclosure.

Throughout this specification and figures like reference numbersidentify like elements.

DETAILED DESCRIPTION

Reference is now made in detail to examples of the present disclosure,examples of which are illustrated in the accompanying drawings. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts. As used herein, the terms“approximately” and “substantially” indicate a range of values within+/−5% of a stated value.

Aspects of the present disclosure relate to lamellar particles andsystems and methods for creating lamellar particles with certainproperties by manipulating these properties (including visual andnon-visual attributes) through chemical conversion. The devices andmethods herein allow for cost-competitive manufacturing of highquantities of metallic pigment. These devices and methods also establishmanufacturing scale capability without excessive capital investment.Further, the resulting particles yield pigment that does not requireadditional passivation and compatibilization processes. The pigment canbe manufactured by a process of metal chemical conversion (MCC). Basedon the selection of materials and structures incorporated into these MCCpigments, the methods described herein offer pigments with a combinationof specific visual and non-visual attributes.

According to the present disclosure, a particle including, but notlimited to a lamellar particle, e.g., pre-conversion lamellar particles100, 200, 300, 400, and/or 500 of FIGS. 1, 5, 9, 13, and 15, can beconverted to a lamellar particle with desired properties (e.g., optical,physical, and/or chemical properties) different than the properties ofthe pre-conversion lamellar particle.

For example, the converted lamellar particle of the present disclosurecan result in specific, desired, and/or enhanced optical properties,such as specific and/or desired wavelengths and/or levels of absorptionand/or reflectance. In particular, the converted lamellar particle ofthe present disclosure can have non-selective absorption of light atcertain wavelengths ranging from about 380 nm to about 760 nm at a levelof 90% and greater of the incident light to make the converted lamellarparticle appear black, non-selective reflectance of incident light atthe level of 10% or greater to make the converted lamellar particleappear gray, non-selective reflectance of incident light at wavelengthsranging from about 380 nm to about 760 nm at the level of 80% andgreater to make the converted lamellar particle appear white, selectivelight reflectance in the visible range of the spectrum to provide visualcolor (e.g., capable of being viewed by the human eye), selective lightreflectance in the visible range of the spectrum at reflectance levelsthat are required to provide visual color combined with metallicreflectance of the metal core, and/or selective reflectance ofelectromagnetic radiation in the infrared part of the spectrum rangingfrom about 0.85 to about 20 microns combined with one or more of thedesired optical properties in the visible range of the spectrum aslisted above.

Further, the converted lamellar particles of the present disclosure canadditionally or alternatively result in specific, desired, and/orenhanced non-optical properties, such as corrosion resistance, heatconductivity (e.g., higher than 1.5 W/mK), electrical conductivity(e.g., higher than 10⁻⁵ S/m), ferromagnetic properties (e.g., ifpre-conversion lamellar particles 100, 200, 300, 400, and/or 500 ofFIGS. 1, 5, 9, 13, and 15 possess ferromagnetic properties), and/orhydrophobic properties (e.g., when conversion chemicals containfunctional groups yielding low surface energy). Further, the convertedlamellar particles of the present disclosure can have heat-rejectingproperties and/or infra-red wavelengths reflecting functions offering analternative way of managing energy conservation. Additionally oralternatively, the converted lamellar particle can provide leafingand/or color flopping options, black colors combined with differentcolor hues appearing at various viewing angles, shieldingelectro-magnetic radiation, a flake format with a large range ofthicknesses, linear dimensions, and/or aspect ratios driven by their endapplication, both metallic and flat color versions of the convertedlamellar particle, heat-reflecting properties, metallic pigments withenhanced environmental stability (stable against heat, water, oxygen,chemical, and/or UV exposure), and/or pigments compatible with variouschemical media, such as paints, inks, rubbers, polymers includingtextiles materials, and ceramic materials including constructionmaterials such as cement and concrete.

A plurality of the converted lamellar particles described herein can becombined to create pigment, including, but not limited to a metalliceffect pigment, a magnetic pigment, an EMI attenuating pigment, anelectrically conductive pigment, a heat conducting pigment, or a pigmentwith a combination of any or all of the preceding properties.

The lamellar particles of the present disclosure (e.g., pre-conversionlamellar particles 100, 200, 300, 400, and/or 500) can be non-naturallyoccurring. In some examples, the lamellar particles (e.g.,pre-conversion lamellar particles 100, 200, 300, 400, and/or 500) can beformed by, for example, sol-gel, chemical bath deposition, plating,physical vapor deposition, and chemical vapor deposition.

The lamellar particles (e.g., pre-conversion lamellar particles 100,200, 300, 400, and/or 500) described herein can be any shape. Lamellarparticles (e.g., pre-conversion lamellar particles 100, 200, 300, 400,and/or 500) can include a first side substantially flat and/or straightin a first direction (e.g., the x-direction of FIG. 1). As illustratedherein, the lamellar particles (e.g., pre-conversion lamellar particles100, 200, 300, 400, and/or 500) can include a second side that issubstantially flat and/or straight in a second direction (e.g., they-direction of FIG. 1) and/or substantially perpendicular to the firstside. In another aspect, the second side can instead be round, pointed,wavy, etc. Further, the second side is not substantially perpendicularto the first side. The lamellar particles (e.g., pre-conversion lamellarparticles 100, 200, 300, 400, and/or 500) can include a third side in athird direction (e.g., the z-direction of FIG. 1). The third side canhave any shape, including, but not limited to, round, rectangular,and/or irregular. In further examples, the lamellar particles (e.g.,pre-conversion lamellar particles 100, 200, 300, 400, and/or 500) can bedescribed as flat, flat with an irregularly-shaped third side (e.g.,corn-flake shaped), flat with a round third side, and/or flat with arectangular third side. In some examples, the pre-conversion lamellarparticles 100, 200, 300, 400, and/or 500 may be a sheet and/or foil.

The lamellar particles (e.g., pre-conversion lamellar particles 100,200, 300, 400, and/or 500) described herein can be any size. Forexample, pre-conversion lamellar particles 100, 200, 300, 400, and/or500 can have any width (e.g., the x-direction of FIG. 1) including, butnot limited to, a width of approximately 2 microns to approximately 200microns, approximately 4 microns to approximately 100 microns, orapproximately 10 microns to approximately 50 microns. Pre-conversionlamellar particles 100, 200, 300, 400, and/or 500 can have any physicalthickness (e.g., the y-direction of FIG. 1) including, but not limitedto, a physical thickness of approximately 0.1 microns to approximately 2microns, approximately 0.5 microns to approximately 1.5 microns, orapproximately 1 micron. Further, pre-conversion lamellar particles 100,200, 300, 400, and/or 500 can have any aspect ratio (e.g., the ratiobetween the width of the pre-conversion lamellar particle and thephysical thickness of the pre-conversion lamellar particle) including,but not limited to, an aspect ratio of approximately 5:1 or greater,approximately 5:1 to approximately 500:1, for example, fromapproximately 10:1 to approximately 250:1, or approximately 100:1.

As illustrated in FIGS. 1-16B, certain properties or attributes of anunconverted portion of pre-conversion lamellar particles 100, 200, 300,400, and/or 500, respectively, can change when subjected to a conversionprocess. In an aspect, at least a part of the unconverted portion caninclude a material that can, at least partially, be converted fromhaving a first property to having a second property. For example, atleast a part of the unconverted portion, if subjected to a conversionprocess, can, at least partially, be converted to change any property,including but not limited to an optical, physical, and/or chemicalproperty. In an aspect, at least a part of the unconverted portion caninclude a material including, but not limited to, aluminum, copper,stainless steel, silver, gold, zinc, iron, bronzes, manganese, titanium,zirconium, vanadium, niobium, chromium, molybdenum, nickel, tungsten,tin, indium, bismuth, alloys of any of these metals, or a combinationthereof. In an aspect, a lamellar particle can include an unconvertedportion 180, 280, 380, 480, and 580 of the lamellar particle, whereinthe unconverted portion 180, 280, 380, 480, and 580 includes a firstmetal.

The conversion process can be any process that converts a first propertyof at least a part of the unconverted portion 180, 280, 380, 480 and580, to a second property. Various conversion chemistries can be used tocontrol color, chromaticity, gloss, leafing, durability, heat orelectrical conductivity, and other properties of the resulting particles(e.g., converted lamellar particles 150, 250, 350, 450, and/or 550). Forexample, the conversion process can convert at least a part of theunconverted portion 180, 280, 380, 480 and 580 from a first color to asecond color and/or convert at least a part of the unconverted portion180, 280, 380, 480 and 580 from a first level of heat conductivity to asecond level.

The conversion process can include subjecting a pre-conversion lamellarparticle to a reactant. The reactant can be in any state, such as plasmastate, gas state, solid state, or liquid state or a combination thereof.The reactant can include any chemical or physical factors that can causea reaction with at least a part of the unconverted portion 180, 280,380, 480 and 580 of the pre-conversion lamellar particle and convert, ina controllable manner, at least a part of the unconverted portion to aconverted portion 170, 270, 370, 470, and 570.

In one example, a water and solvent-borne environment can be used as thereactant. In some examples, the conversion process can include the useof various types of chemical reactants, including batch and continuousstirred tank reactants, tubular reactants, tumbling bed reactants,fluidized bed reactants, continuous flow tube and batch furnaces. Insuch examples, pre-conversion lamellar particles 100, 200, 300, 400, or500 can be subjected to chemical(s) that cause at least partialconversion of pre-conversion lamellar particles 100, 200, 300, 400, 500or at least a part of the unconverted portion 180, 280, 380, 480 and580.

The chemical bath composition used herein can include an inorganiccompound or an organic compound. An example of an inorganic compound caninclude at least one of sulfur, sulfides, sulfates, oxides, hydroxides,isocyanates, thiocyanates, molybdates, chromates, permanganates,carbonates, thiosulfates, colloidal metals, inorganic salts, andmixtures thereof. An example of an organic compound can include anorganic compound that contains sulfur, such as thiols, thioamine,oxythio amines, thiourea, thiocyanates; nitrogen, such as amines, andisocyanates; oxygen; silicon, such as silanes; or a combination thereof.Further, the chemical bath can include at least one of inorganic ororganic salts of metals or metallic organic compounds of metals. In yetanother aspect, the chemical bath can include at least one of anoxidizing agent, a surface modifier, and an inhibitor.

In an aspect, the unconverted portion 180, 280, 380, 480, and 580 of aconverted lamellar particle 150, 250, 350, 450, and 550 can provide alight reflectance in a spectral region ranging from 0.4 to 20 micronsand the converted portion 170, 270, 370, 470, and 570 can absorb lightin a selected region of this spectral range. In some examples, theselected regions can be in the visible range. In an aspect, theunconverted portion 180, 280, 380, 480, and 580 of a converted lamellarparticle can provide infrared reflectance.

The converted portion 170, 270, 370, 470, and 570 can absorb light in aselected region capable of being viewed by the human eye. The convertedportion can modulate light in the visible range to create a desiredcolor. For example, converted portion 170, 270, 370, 470, and 570 canappear red to the human eye (e.g., approximately 380 nm to approximately600 nm), black to the human eye (e.g., absorbing approximately 380 nm toapproximately 760 nm), or white. Further, for example, converted portion170, 270, 370, 470, and 570 can appear blue to the human eye (e.g.,absorbing approximately 500 nm to approximately 760 nm), or can appeargreen to the human eye (e.g., absorbing approximately 380 nm toapproximately 500 nm and also absorbing approximately 600 nm toapproximately 760 nm).

The converted portion 170, 270, 370, 470, and 570 can absorb light in aselected near-infrared region of the spectrum capable of being detectedby electronic sensors. The converted portion can modulate light in thenear-infrared range to provide a selected level of absorption. Forexample, converted portion 170, 270, 370, 470, and 570 can absorb lightfrom approximately 720 nm to approximately 1100 nm, or can absorb lightfrom approximately 950 nm to approximately 1700 nm.

In some examples, the unconverted external layer and/or the unconvertedinner core of the pre-conversion lamellar particles can includeadditives (e.g., dyes) for selectively absorbing or reflecting energy.In some examples, the unconverted external layer and/or unconvertedinner core of the pre-conversion lamellar particles do not includeadditives (e.g., dyes) for selectively absorbing or reflecting energy.

After the conversion process, the converted portion of a convertedlamellar particle can have any thickness, including, but not limited toapproximately 0.01 microns to approximately 0.9 microns, approximately0.1 microns to approximately 0.8 microns, or approximately 0.5 microns.The total size of the converted lamellar particle and/or thickness ofthe converted portion of the converted lamellar particle can depend on avariety of factors including, but not limited to, the extent to which areaction, such as a chemical reaction, converts the pre-conversionlamellar particle. The different optical and non-optical properties canbe achieved by adjusting varying aspects of the pre-conversion lamellarparticle and the conversion process. For example, the converted lamellarparticle can have different optical and/or non-optical properties basedon the material, structure, size, shape, and/or aspect ratio of thepre-conversion lamellar particle, type of applied chemical treatment,and process conditions, such as concentrations of reactive ingredients,applied additives, pH, temperature, type of agitation, and length ofexposure. In some examples, the converted lamellar particle can have atleast one different non-optical property than the pre-conversionlamellar particle. In one example, the converted lamellar particle canhave a different electrical conductivity and/or thermal conductivitythan the pre-conversion lamellar particle. The measured sheet resistancecan be 100 Ohms or less and/or the thermal conductivity would be 3 W*m⁻¹K⁻¹ or higher. The resistance and the thermal conductivity of theconverted lamellar particle can depend on the metal used in theconversion process.

The amount of lamellar particle and/or the specific layers (inner core,internal layer, and/or external layer, etc.) that are converted candepend on a variety of factors, including but not limited, thecomposition of the chemical conversion process (e.g., the composition ofthe chemical bath), its concentration, the time of exposure to theconversion process, the temperature during the conversion process,and/or the structure of the pre-conversion lamellar particle (e.g., theinclusion of a corrosion barrier, an internal layer, and/or barrierlayer). In addition, the reactants used in the chemical conversionprocess can include self-inhibiting properties after converting to acertain depth into the pre-conversion lamellar particle. For example,0.5 percent of the pre-conversion lamellar particle can be converted or100 percent can be converted, including all the ranges of percentconversion in between.

Subjecting the pre-conversion lamellar particle to a chemical conversionprocess can convert the pre-conversion lamellar particle to a convertedlamellar particle (e.g., converted lamellar particles 150, 250, 350,450, and/or 550) by converting a least a part of the pre-conversionlamellar particle. For example, 0.5 percent of the pre-conversionlamellar particle can be converted or 100 percent can be converted,including all the ranges of percent conversion in between. In an aspect,at least a part of the lamellar particle is converted (e.g., convertedportions of lamellar particle 170, 270, 370, 470, and 570), whileanother part remains unconverted (e.g., unconverted portions of thelamellar particle 180, 280, 380, 480, and 580). In other examples, theentire lamellar particle is converted. In such examples, a convertedlamellar particle would no longer include a material, such as metal, butwould instead include a chemical compound of the material, such as achemical compound of the metal.

The converted portions of lamellar particle 170, 270, 370, 470, and 570can include at least a chemical compound of a material, such as a firstmetal, included in the unconverted portion 180, 280, 380, 480, and 580of the pre-conversion lamellar particle. For example, if the unconvertedexternal layer 102, 202, 302, 402, and 502 of the pre-conversionlamellar particle 100, 200, 300, 400, 500 included copper and thepre-conversion lamellar particle was subjected to sulfur during aconversion process, the converted portion 170, 270, 370, 470, 570 of theconverted lamellar particle 150, 250, 350, 450, 550 could include achemical compound of copper, i.e., copper sulfide, and the unconvertedportion 180, 280, 380, 480, 580 of the converted lamellar particle couldinclude copper. In some examples, a pre-conversion lamellar particle canbe completely converted or completely unconverted, including all rangesof percent conversion in between.

In an aspect, if a pre-conversion lamellar particle has an inner coreand an external layer, such as shown in FIG. 5, then each of the innercore and the external layer can be completely converted or completelyunconverted, including all ranges of percent of conversion in between.For example, the converted portion 170, 270, 370, 470, and 570 of theconverted lamellar particle 150, 250, 350, 450, and 550 can include (i)converted external layer 204, 304, 404, and 504; and/or (ii) theconverted external layer 204, 304, 404, and 504 and the converted innercore 206, 306, 406, and 506. The unconverted portion 180, 280, 380, 480,and 580 of the converted lamellar particle 150, 250, 350, 450, and 550can include (i) the unconverted inner core 210, 310, 410, and 510;and/or (ii) the unconverted external layer 202, 302, 402, and 502 andthe unconverted inner core 210, 310, 410, and 510. In an aspect, in someexamples, the entire unconverted external layer 102, 202, 302, 402, and502 is converted. In some examples, the entire unconverted externallayer 102, 202, 302, 402, and 502 is converted, as well as at least apart of the unconverted inner core 210, 310, 410, 510. In some examples,the unconverted portions of the lamellar particle 180, 280, 380, 480,and 580 can include a plurality of layers, such as an internal layer420, 520 and/or a plurality of materials.

In some examples, the plurality of layers can include at least twodifferent materials, such as two different metals. Some or all of thedifferent materials can be a metal(s). In an aspect, each layer of theplurality of layers can be made of a different material than each otherlayer of the plurality of layers.

In an aspect, the converted portion 170, 270, 370, 470, and 570 of thelamellar particle can be external to a surface of the unconvertedportion 180, 280, 380, 480 and 580, which can include an unconvertedexternal layer 202, 302, 402, and 502, an internal layer 420, 520,and/or an unconverted inner core 110, 210, 310, 410, and 510.

Any of the lamellar particles described herein or created by processesdescribed herein can be used in a variety of applications. For example,among other applications, the converted lamellar particles can be usedfor camouflage, sensing, charge dissipation, dissipating heat, shieldingagainst electromagnetic interferences, and decorations. Morespecifically, the converted lamellar particles and/or the conversionprocess can be used in textiles. The converted lamellar particles can beused for pigmentation of textiles and/or adding additional non-visualattributes to fabrics. For example, the converted lamellar particles canbe used to create heat-rejecting fabrics, infrared-rejecting fabrics,electromagnetic radiation shielding fabrics, heat conducting fabrics,electrically-conductive yarns and fabrics, yarns and fabrics withferromagnetic properties, camouflage, and/or radiation (e.g., infrared,heat, electromagnetic) shielding properties. In some examples, convertedlamellar particles used for textiles may be smaller than those used forother applications (e.g., automotive and architectural). For example,converted lamellar particles used in textile applications can beapproximately 2 microns, or smaller than approximately 10 microns.Converted lamellar particles used in automotive applications can beapproximately 8 microns to approximately 200 microns and convertedlamellar particles used in architectural applications can be up toapproximately 200 microns.

The converted lamellar particles and/or the conversion processes canalso be used as pigments for specialty paints, inks, varnishes, andcoatings that can provide coloration together with non-visualattributes. For example, converted lamellar particles and/or theconversion processes can be used in pigments for metallic inks, heat andIR rejection, electromagnetic radiation shielding, heat conductivity,electrical conductivity, and/or ferromagnetic properties

The converted lamellar particles and/or the conversion processes canalso be used in construction and architectural materials. For example,the converted lamellar particles can be used in heat-rejecting paintsfor architectural applications, heat-rejecting roofing, siding, anddecking materials, heat-rejecting cement and concrete, electromagneticshielding paints for architectural and construction applications, and/orstatic charge controlling paints

The converted lamellar particles and/or the conversion processes can beused in various automotive applications, including, but not limited to,LIDAR, heat-reflecting exterior automotive pigments and coatings, blacksingle component pigments with various color hue flop, semi-metallicpigments with unique color hues, and/or heat and/or static chargedissipating pigments for automotive interior applications.

The converted lamellar particles and/or the conversion processes can beused in various applications in cosmetics and healthcare, for example,direct skin-on application of pigments for esthetic, protective,diagnostic, and/or medical treatments.

The converted lamellar particles and/or the conversion processes can beused in various other applications, including, but not limited to, RFantennas, magnetic taggants, special effect pigments, and pigments forelectroluminescent inks and coatings.

The pre-conversion lamellar particles of the present disclosure can haveany layer structure. Pre-conversion lamellar particles 100, 200, 300,400, and 500 are merely exemplary. The pre-conversion lamellar particlescan include any number of layers, such as a plurality of layers. Theselayer(s) can be made of any material, such as a first metal, in anyconfiguration, and/or in any order. In an aspect, the pre-conversionlamellar particles 100, 200, 300, 400, and 500 can include anunconverted inner core 210, 310, 410, and 510 and an unconvertedexternal layer 202, 302, 402, and 502. In another aspect, thepre-conversion lamellar particles 100, 200, 300, 400, and 500 caninclude additional layers, such as an internal layer 420, 520, betweenthe unconverted inner core 210, 310, 410, and 510 and the unconvertedexternal layer 202, 302, 402, and 502. Further, unconverted inner core210, 310, 410, and/or 510 can include a plurality of layers.

In one example, as illustrated in FIG. 1, the pre-conversion lamellarparticle 100 can be a monolithic particle composed of a single material(e.g., a single metal, such as a first metal). Pre-conversion lamellarparticle 100 consists of one layer; unconverted external layer 102. Oncesubjected to a conversion process (including, but not limited to, thosedescribed above), pre-conversion lamellar particle 100 can be convertedto a converted lamellar particle, including, but not limited to,converted lamellar particle 150 of FIG. 2, 3, or 4. Converted lamellarparticle 150 can include a converted portion 170 and an unconvertedportion 180. The unconverted portion 180 can include a first metal andthe converted portion 170 can include a chemical compound of the firstmetal. In this example, because the pre-conversion lamellar particle 100consists of unconverted external layer 102, the converted portion of theexternal layer 104 is the same as the converted portion of the lamellarparticle 170, as shown in FIG. 2. Additionally, the unconverted portionof the external layer 102 is the same as the unconverted portion of thelamellar particle 180.

The physical thickness L₁ of converted lamellar particle 150 can beabout the same physical thickness L₀ of the pre-conversion lamellarparticle 100. Thus, the physical thickness L₁ can be approximately 0.1microns to approximately 2 microns, approximately 0.5 microns toapproximately 1.5 microns, or approximately 1 micron. In some examples,however, thickness L₁ of converted lamellar particle 150 can be greaterthan the physical thickness L₀ of the pre-conversion lamellar particle100. For example, the conversion process can cause at least a portion ofthe pre-conversion lamellar particle 100 to expand. As shown in FIG. 2,L₁ is the sum of the thickness L₂ of the unconverted portion 102/180 andthe two thicknesses L₃ of the converted portion 104/170 on either sideof unconverted portion 102/180.

In an aspect, the thickness L₃ of the converted portion 104/170 canrange from about one percent to about 100 percent of the total thicknessL₁ of the converted lamellar particle 150. In an example, as shown inFIG. 2, the unconverted portion 102/180 can have a physical thickness L₂which is greater than the physical thickness L₃ of the converted portion104/170. In another example, as shown in FIG. 3, the unconverted portion102/180 can have a physical thickness L₂ which is less than thethickness L₃ of the converted portion 104/170. In yet another example,as shown in FIG. 4, the unconverted portion 102/180 and the convertedportion 104/170 can have variable physical thicknesses. In this example,the converted portion 104/170 can include a first thickness L₃ and asecond thickness L₄. The physical thickness of the unconverted portion102/180 can vary in accordance with the physical thickness of theconverted portion 104/170.

In another example, as illustrated in FIG. 5, the pre-conversionlamellar particle 200 can include an unconverted external layer 202external to at least three sides of an unconverted inner core 210). Insome examples, the unconverted external layer 202 can be external to atleast four sides, at least five sides, or at least six sides of theunconverted inner core 210. The unconverted external layer 202 cancompletely encapsulate the unconverted inner core 210. The unconvertedinner core 210 can be made of a first material and the unconvertedexternal layer 202 can be made of a second material different than thefirst material. In some examples, the first material can be a firstmetal and the second material can be a second metal. In some examples,the first material can include, but is not limited to, aluminum, copper,stainless steel, silver, gold, zinc, iron, bronzes, manganese, titanium,zirconium, vanadium, niobium, chromium, molybdenum, nickel, tungsten,tin, indium, bismuth, alloys of any of these metals or a combinationthereof. The second material can include, but is not limited to (i)metals or metal alloys, such as one or more of aluminum, copper-silver,gold, zinc, iron, bronzes, manganese, titanium, zirconium, vanadium,niobium, chromium, molybdenum, nickel, tungsten, tin, indium, bismuth,alloys of any of these metals or a combination thereof, (ii)dielectrics, such as metal oxides, glasses, chalcogenides, halides,sulfides, minerals, synthetic micro and nano-crystals, organic andinorganic polymers, (iii) conductive materials, such as indium-tinoxide, tin oxide, metal doped oxides, and conductive polymers, and/or(iv) metalloids and non-metals, such as silicon, germanium, carbon,graphite, and graphene. The materials listed in (ii)-(iv) can bepartially and/or not completely converted when subjected to chemicalconversion. The materials listed in (ii)-(iv) can provide variousnon-visual attributes or can act as a conversion barrier. For example,the first material can be less reactive to a given conversion process,thus creating a location within the lamellar particle in which theconversion is likely to stop, i.e., functioning as a “conversionbarrier.” Further, in some examples, the unconverted inner core 210and/or the unconverted external layer 202 can include a plurality oflayers, such as an internal layer, and/or a plurality of materials. Insome examples, each layer of the plurality of layers can include thesame materials or each layer of the plurality of layers can includedifferent materials.

Once subjected to a conversion process including, but not limited to,those described above, pre-conversion lamellar particle 200 can beconverted to a converted lamellar particle, including, but not limitedto, converted lamellar particle 250 of FIG. 6, 7, or 8. Convertedlamellar particle 250 can include a converted portion 270 and anunconverted portion 280. The unconverted portion 280 can include a firstmetal and the converted portion 270 can include a chemical compound ofthe first metal. In some examples, about one percent to about 100percent of unconverted external layer 202 can be converted to aconverted external layer 204. In some examples, about zero percent toabout 100 percent of unconverted inner core 210 can be converted to aconverted inner core 206.

In the example illustrated in FIG. 6, 100 percent of the unconvertedexternal layer 202 was converted to converted external layer 204 andzero percent of unconverted inner core 210 was converted. Thus, theconverted portion of the lamellar particle 270 is the same as theconverted external layer 204 and the unconverted portion of the lamellarparticle 280 is the same as unconverted inner core 210

In the example illustrated in FIG. 7, less than 100 percent of theunconverted external layer 202 was converted to converted external layer204 and zero percent of unconverted inner core 210 was converted. Thus,the converted portion of the lamellar particle 270 includes theconverted external layer 204; and the unconverted portion of thelamellar particle 280 includes the unconverted external layer 202 andthe unconverted inner core 210. In an aspect, with regard to FIG. 7, theunconverted external layer 202 can include a first metal and convertedexternal layer 204 can include a chemical compound of the first metal.

In the example illustrated in FIG. 8, 100 percent of the unconvertedexternal layer 202 was converted to converted external layer 204 and atleast a portion of unconverted inner core 210 was converted to convertedinner core 206. Thus, the converted portion of the lamellar particle 270includes the converted external layer 204 and the converted inner core206; and the unconverted portion of the lamellar particle 280 includesthe unconverted inner core 210. In an aspect, with regard to FIG. 8, theunconverted inner core 210 can include a first metal and converted innercore 206 can include a chemical compound of the first metal.

In an additional example, as illustrated in FIG. 9, the pre-conversionlamellar particle 300 can include an unconverted inner core 310sandwiched by unconverted external layers 302. For example, unconvertedexternal layers 302 can be external to a first side of the unconvertedinner core 310 and a second side of the unconverted inner core 310opposite the first side, but not external to any of the other sides,i.e., the unconverted external layers 302 do not encapsulate theunconverted inner core 310. The unconverted inner core 310 can be madeof a first material, and the unconverted external layers 302 can be madeof a second material. In some examples, the first material is a firstmetal and the second material is a second metal. In some examples, thefirst material can include, but is not limited to, aluminum, copper,stainless steel, silver, gold, zinc, iron, bronzes, manganese, titanium,zirconium, vanadium, niobium, chromium, molybdenum, nickel, tungsten,tin, indium, bismuth, alloys of any of these metals or a combinationthereof. The second material can include, but is not limited to (i)metals or metal alloys, such as one or more of aluminum, copper,stainless steel, silver, gold, zinc, iron, bronzes, manganese, titanium,zirconium, vanadium, niobium, chromium, molybdenum, nickel, tungsten,tin, indium, bismuth, alloys of any of these metals or a combinationthereof, (ii) dielectrics, such as metal oxides, glasses, chalcogenides,halides, sulfides, minerals, synthetic micro and nano-crystals, organicand inorganic polymers, (iii) conductive materials, such as indium-tinoxide, tin oxide, metal doped oxides, and conductive polymers, and/or(iv) metalloids and non-metals, such as silicon, germanium, carbon,graphite, and graphene. The materials listed in (ii)-(iv) can partiallyand/or not completely converted when subjected to chemical conversion.The materials listed in (ii)-(iv) can provide various non-visualattributes or can act as conversion barrier. For example, the firstmaterial can be less reactive to a given conversion process, thuscreating a location within the lamellar particle in which the conversionis likely to stop i.e., can function as a “conversion barrier.” Further,in some examples, the lamellar particle can include a plurality oflayers, such as an internal layer, and/or a plurality of materials.

Once subjected to a conversion process including, but not limited to,those described above, pre-conversion lamellar particle 300 can beconverted to a converted lamellar particle including, but not limitedto, converted lamellar particle 350 of FIGS. 10A-10B, 11A-B, or 12A-B.Converted lamellar particle 350 can include a converted portion 370 andan unconverted portion 380. The unconverted portion 380 can include afirst metal and the converted portion 370 can include a chemicalcompound of the first metal. In some examples, about one percent toabout 100 percent of unconverted external layers 302 can be converted toconverted external layers 304. In some examples, zero percent to 100percent of unconverted inner core 310 can be converted to convertedinner core 306.

In the example illustrated in FIG. 10A, 100 percent of the unconvertedexternal layer 302 was converted to converted external layer 304 andzero percent of the unconverted inner core 310 was converted. Thus, theconverted portion of the lamellar particle 370 is the same as convertedexternal layer 304; and the unconverted portion of the lamellar particle380 is the same as the unconverted inner core 310.

In the example illustrated in FIG. 10B, 100 percent of the unconvertedexternal layer 302 was converted to converted external layer 304 and asmall percent (at least a part) of the unconverted inner core 310 wasconverted to converted inner core 306. In particular, the sides of theunconverted inner core 310 that did not have an unconverted externallayer 302 external thereto were converted. Thus, the converted portionof the lamellar particle 370 includes the converted external layer 304and at least a part, i.e., the sides of, the converted inner core 306;and the unconverted portion of the lamellar particle 380 is the same asthe unconverted inner core 310. In an aspect, the unconverted inner core310 can include a first metal and the converted inner core 306 caninclude a chemical compound of the first metal.

In the example illustrated in FIG. 11A, less than 100 percent of theunconverted external layer 302 was converted to converted external layer304 and zero percent of unconverted inner core 310 was converted. Thus,the converted portion of the lamellar particle 370 includes theconverted external layer 304; and the unconverted portion of thelamellar particle 380 includes the unconverted external layers 302 andthe unconverted inner core 310. In an aspect, the unconverted externallayer 302 can include a first metal and the converted external layer 304can include a chemical compound of the first metal.

In the example illustrated in FIG. 11B, less than 100 percent of theunconverted external layer 302 was converted to converted external layer304 and a percentage (at least a part) of unconverted inner core 310 wasconverted to converted inner core 306. In particular, the sides of theunconverted inner core 310 that did not have an unconverted externallayer 302 external thereto were converted. Thus, the converted portionof the lamellar particle 370 includes the converted external layer 304and at least a part, i.e., the sides of the converted inner core 306;and the unconverted portion of the lamellar particle 380 includes theunconverted external layers 302 and the unconverted inner core 310. Inan aspect, the unconverted inner core 310 can include a first metal andthe converted inner core 306 can include a chemical compound of thefirst metal. In another aspect, the unconverted external layer 302 caninclude the first metal and the converted external layer 304 can includea chemical compound of the first metal.

In the example illustrated in FIG. 12A, 100 percent of the unconvertedexternal layer 302 was converted to converted external layer 304 and atleast a portion of the unconverted inner core 310 was converted toconverted inner core 306. Thus, the converted portion of the lamellarparticle 370 includes the converted external layers 304 and theconverted inner core 306; and the unconverted portion of the lamellarparticle 380 includes the unconverted inner core 310. In an aspect, theunconverted inner core 310 can include a first metal and the convertedinner core 306 can include a chemical compound of the first metal.

In the example illustrated in FIG. 12B, 100 percent of the unconvertedexternal layer 302 was converted to converted external layer 304 and asmall percentage (i.e., at least a part) of the unconverted inner core310 was converted to converted inner core 306. In particular, the sidesof the unconverted inner core 310 that did not have an unconvertedexternal layer 302 external thereto were converted. Thus, the convertedportion of the lamellar particle 370 includes the converted externallayers 304 and the converted inner core 306; and the unconverted portionof the lamellar particle 380 includes the unconverted inner core 310. Inan aspect, the unconverted inner core 310 can include a first metal andthe converted inner core 306 can include a chemical compound of thefirst metal.

In the example illustrated in FIG. 13, the pre-conversion lamellarparticle 400 can include at least three layers. For example, thepre-conversion lamellar particle 400 can include an unconverted innercore 410, an internal layer 420, and/or an unconverted external layer402. In some examples, pre-conversion lamellar particle 400 can includea first material in the unconverted external layer 402 encapsulating asecond material in the unconverted inner core 410 with an internal layer420 between the first and second materials. The internal layer 420 canbe external of two sides (e.g., sandwiching unconverted inner core 410)to six sides (e.g., encapsulating unconverted inner core 410). In someexamples, the first material can include, but is not limited to,aluminum, copper, stainless steel, silver, gold, zinc, iron, bronzes,manganese, titanium, zirconium, vanadium, niobium, chromium, molybdenum,nickel, tungsten, tin, indium, bismuth, alloys of any of these metals ora combination thereof. The second material can include, but is notlimited to (i) metals or metal alloys, such as one or more of aluminum,copper, stainless steel, silver, gold, zinc, iron, bronzes, manganese,titanium, zirconium, vanadium, niobium, chromium, molybdenum, nickel,tungsten, tin, indium, bismuth, alloys of any of these metals or acombination thereof, (ii) dielectrics, such as metal oxides, glasses,chalcogenides, halides, sulfides, minerals, synthetic micro andnano-crystals, organic and inorganic polymers, (iii) conductivematerials, such as indium-tin oxide, tin oxide, metal doped oxides, andconductive polymers, and/or (iv) metalloids and non-metals such assilicon, germanium, carbon, graphite, and graphene. The internal layer420 can include any material, including materials (ii)-(iv). Thematerials listed in (ii)-(iv) can be a less reactive to a chemicalconversion process. Their function can be to provide other non-visualattributes or to act as conversion barrier. For example, the internallayer 420 can be less reactive to a given conversion process, thuscreating a location with the lamellar particle in which the conversionis likely to stop, i.e., function as a “conversion barrier.” Further, insome examples, the unconverted inner core 410, and/or the unconvertedexternal layer 402 can include a plurality of layers and/or a pluralityof materials.

Once subjected to a conversion process including, but not limited tothose described above, pre-conversion lamellar particle 400 can beconverted to a converted lamellar particle, including but not limited toconverted lamellar particle 450 of FIG. 14. Converted lamellar particle450 can include a converted portion 470 and an unconverted portion 480.The unconverted portion 480 can include a first metal and the convertedportion 470 can include a chemical compound of the first metal. In someexamples, about one percent to 100 percent of unconverted external layer402 can be converted to converted external layer 404. In some examples,zero percent to 100 percent of unconverted inner core 410 can beconverted to converted inner core 406. In some examples, zero percent to100 percent of internal layer 420 can be converted.

In the example illustrated in FIG. 14, 100 percent of the unconvertedexternal layer 402 was converted to converted external layer 404; andnone of internal layer 420 and unconverted inner core 410 wereconverted. Thus, the converted portion of the lamellar particle 470 isthe same as converted external layer 404; and the unconverted portion ofthe lamellar particle 480 is the internal layer 420 and the unconvertedinner core 410. Similar to converted lamellar particles 150, 250, and350, the definition of the converted portion of the lamellar particle470 and unconverted portion of lamellar particle 480 depends on whichlayers were converted and to what extent. In an aspect, the unconvertedinner core 410 can include a first metal, the internal layer 420 caninclude a material from those listed in (ii)-(iv) above, such as adielectric or barrier layer, and the converted inner core can include achemical compound of the first metal. In another aspect, the unconvertedexternal layer can include a first metal and the converted externallayer 404 can include a chemical compound of the first metal.Additionally, or alternatively, the unconverted inner core 410 caninclude a first metal, unconverted external layer 402 can include thefirst metal, and the converted external layer 404 can include a chemicalcompound of the first metal.

In an additional example, as illustrated in FIG. 15, the pre-conversionlamellar particle 500 can include an unconverted inner core 510sandwiched by the unconverted external layer 502, with an internal layer520 between the unconverted inner core 520 and the unconverted externallayer 502 on each side. For example, unconverted external layer 502 canbe external to the internal layer 520 which can be in turn external to afirst side and a second side opposite the first side of the unconvertedinner core 510, but not external to any of the other sides (e.g., atleast four sides of the unconverted inner core 510 are free ofunconverted external layers 502 and/or barrier layers 520). Theunconverted external layer 502 can be made of a second material and theunconverted inner core 510 can be made of a first material. At least thefirst material can be a metal. In some examples, the first material andthe second material can include, but are not limited to, aluminum,copper, stainless steel, silver, gold, zinc, iron, bronzes, manganese,titanium, zirconium, vanadium, niobium, chromium, molybdenum, nickel,tungsten, tin, indium, bismuth, alloys of any of these metals or acombination thereof. The second material can include, but is not to (i)metals, such as one or more of aluminum, copper, stainless steel,silver, gold, zinc, iron, bronzes, manganese, titanium, zirconium,vanadium, niobium, chromium, molybdenum, nickel, tungsten, tin, indium,bismuth, alloys of any of these metals or a combination thereof. Theinternal layer 520 can include, but is not limited to (ii) dielectrics,such as metal oxides, glasses, chalcogenides, halides, sulfides,minerals, synthetic micro and nano-crystals, organic and inorganicpolymers, (iii) conductive materials, such as indium-tin oxide, tinoxide, metal doped oxides, and conductive polymers, and/or (iv)metalloids and non-metals, such as silicon, germanium, carbon, graphite,and graphene. The materials listed in (ii)-(iv) can partially and/or notcompletely converted when subjected to chemical conversion. The functionof the materials listed in (ii)-(iv) can provide various non-visualattributes, i.e., can act as conversion barrier. For example, theinternal layer 520 can be less reactive to a given conversion process,thus creating a location within the lamellar particle 500 in which theconversion is likely to stop or a “conversion barrier.” Further, in someexamples, the unconverted inner core 510 and/or the unconverted externallayer 502 can include a plurality of layers and/or a plurality ofmaterials.

Once subjected to a conversion process including, but not limited tothose described above, pre-conversion lamellar particle 500 can beconverted to a converted lamellar particle, including, but not limited,to converted lamellar particle 550 of FIGS. 16A-B. Converted lamellarparticle 550 can include a converted portion 570 and an unconvertedportion 580. The unconverted portion 580 can include a first metal andthe converted portion 570 can include a chemical compound of the firstmetal. In some examples, about one percent to 100 percent of theunconverted external layers 502 can be converted to converted externallayers 504. In some examples, zero percent to 100 percent of unconvertedinner core 510 can be converted to converted inner core 506. In someexamples, zero percent to 100 percent of internal layers 520 can beconverted.

In the example illustrated in FIG. 16A, some or all of the unconvertedexternal layer 502 was converted to the converted external layer 504;and none of the internal layers 520 and the unconverted inner core 510were converted. Thus, the converted portion of the lamellar particle 570includes the converted external layer 504; and the unconverted portionof the lamellar particle 580 can include internal layers 520 and theunconverted inner core 510. In some examples, the unconverted portion580 can also include an unconverted external layer 502 (not shown in theFigures). Similar to converted lamellar particles 150, 250, 350, and450, the definition of the converted portion of the lamellar particle570 and unconverted portion of lamellar particle 580 depends on whichlayers were converted and to what extent.

In an aspect, the unconverted inner core 510 can include a first metal,the internal layer 520 can include a material from those listed in(ii)-(iv) above, such as a dielectric or barrier layer, and theconverted inner core can include a chemical compound of the first metal.In another aspect, the unconverted external layer can include a firstmetal, the internal layer 520 can include a material from those listedin (ii)-(iv) above, such as a dielectric or barrier layer, and theconverted external layer 504 can include a chemical compound of thefirst metal. Additionally, or alternatively, the unconverted inner core510 can include a first metal, unconverted external layer 502 caninclude the first metal, and the converted external layer 504 caninclude a chemical compound of the first metal.

In the example illustrated in FIG. 16B, some or all of the unconvertedexternal layer 502 was converted to the converted external layer 504;and none of the internal layers 520 and the unconverted inner core 510were converted. Thus, the converted portion of the lamellar particle 570includes the converted external layer 504; and the unconverted portionof the lamellar particle 580 can include internal layers 520 and theunconverted inner core 510. In some examples, the unconverted portion580 can also include an unconverted external layer 502 (not shown in theFigures). Similar to converted lamellar particles 150, 250, 350, and450, the definition of the converted portion of the lamellar particle570 and unconverted portion of lamellar particle 580 depends on whichlayers were converted and to what extent. In an aspect, the unconvertedinner core 510 can include a first metal and the converted inner core506 can include a chemical compound of the first metal. In anotheraspect, the unconverted external layer can include a first metal, theinternal layer 520 can include a material from those listed in (ii)-(iv)above, such as a dielectric or barrier layer, and the converted externallayer 504 can include a chemical compound of the first metal.Additionally, or alternatively, the unconverted inner core 510 caninclude a first metal, unconverted external layer 502 can include thefirst metal, and the converted external layer 504 can include a chemicalcompound of the first metal.

A pigment comprising a plurality of the lamellar particles of claim 1that include at least two of the following properties: magnetic, EMIattenuating, electrically conductive, and heat conductive.

A method, comprising: chemically converting a first material of alamellar particle into a compound of the first material. The firstmaterial is metal. Prior to the chemical conversion, the lamellar has anaspect ratio at least 2:1. The first material is external to orsurrounds a second material. The compound of the first materialcomprises a sulfide, phosphate, chromate, molybdate, permanganate,vanadate, sulfate, carbonate, oxides, hydroxides, nitrates,tungstanates, titanates, fluorotitanates, or a combination thereof. Thechemical conversion is performed by a reactant and the reactant is in aform of at least one of solid state, liquid state, vapor state, andplasma state. The liquid state is a chemical bath. The solid state is atumbling bed of pre-flakes. The vapor state is a fluidized bed or apacked bed. For the plasma state, the reactant is introduced in the formof ionized gas or is introduced into a plasma ignited in a carrier gassuch as noble gases, oxygen, nitrogen, CO2, or introducing oxidationthrough heat. The chemical bath comprises water and a solvent. Thechemical bath comprises at least one of an inorganic compound and anorganic compound. The inorganic compound comprises at least one ofsulfur, sulfides, sulfates, oxides, hydroxides, isocyanates,thiocyanates, molybdates, chromates, permanganates, carbonates,thiosulfates, and inorganic salts.

The organic compound comprises at least one of organic compoundcontaining sulfur, nitrogen, oxygen and combinations thereof. Theorganic compound comprises at least one of thiols, amines, thioamines,oxythio amines, thiourea, isocyanates, thiocyanates, and silanes. Thechemical bath comprises at least one of inorganic and organic salts ofmetals or metalorganic compounds of metals. The chemical bath comprisesan oxidizing agent. The chemical bath comprises at least one of asurface modifier and inhibitors. The lamellar particle comprises a firstmaterial and a second material at least partially encapsulating thefirst material. The second material and the first material aredifferent. The second material is deposited on the first material by atleast one of metal plating processes, roll-to-roll metallizationprocesses, chemical bath deposition, physical vapor deposition, andchemical vapor deposition. The method further comprises depositing aninternal layer between at least a portion of the second material and thefirst material. The internal layer is deposited by one of sol-gel,chemical bath deposition, plating, physical vapor deposition, andchemical vapor deposition.

A lamellar particle comprising a first portion including a firstmaterial, and a second portion external to the first portion, whereinthe second portion includes a chemical compound of the first material.

As shown in FIGS. 21-24, there is also disclosed a functional lamellarparticle 700, comprising an unconverted portion 280 of the lamellarparticle, wherein the unconverted portion 280 includes a first metal; aconverted portion 270 of the lamellar particle disposed external to asurface of the unconverted portion 280, wherein the converted portion270 includes a chemical compound of the first metal; and a functionalcoating 710 disposed external to a surface of the converted portion 270.The functional lamellar particle 700 can also include an unconvertedinner core 210, a converted inner core 206, an unconverted externallayer 202, and a converted external layer 204, as disclosed above withregard to FIGS. 6-8.

The functional coating 710 can provide at least one function to thelamellar particle including adjusting porosity, adjusting surface area,controlling shear properties of a host system, controllingdispersibility in a host system, adjusting chemical compatibility andreactivity of surfaces of the lamellar particle, providing a barrier(chemical and/or physical), providing mechanical protection, chemicallycapping compounds on the surface of the converted portion, adjustingsurface energy, adjusting hydrophilicity/hydrophobicity, controllingsolvent intake, controlling orientation and alignment of the lamellarparticle in a host system, increasing electrical and heat conductivity,adding or increasing magnetic susceptibility, improving absorption orreflectance of wavelengths in various parts of the spectral region,providing ultraviolet protection to materials present in the lamellarpigments, adding new spectral attributes such as fluorescence,phosphorescence, QD effects, unique elemental signatures for XRFdetection, thermochromic, and photochromic effects), adding metallicabsorber functions for accentuating spectral and non-spectralattributes, and combinations thereof. As an example, thermochromiceffects can be achieves with W-doped VO₂), photochromic effects can beachieved from doping with AgCl, and electrochromic effects can beachieved with WO₃.

In an aspect, the functional lamellar particles 700 can be used forclassified, decorative, and security applications.

The functional coating 710 can be a layer of a metal oxide; a metal; ataggant; a surfactant; a steric stabilizer; ormosil; organic compounds;polymer; dyes; UV absorbers; antioxidants; heat treatments; andcombinations thereof.

In an aspect, the functional coating 710 can be a metal oxide chosenfrom SiO₂, Al₂O₃, TiO₂, ZnO, Nb₂O₃, B₂O₃, WO₃, AgCl-doped SiO₂,Y₂O₃-stabilized ZrO₂, indium tin oxide, VO₂ and combinations thereof.The metal oxide can be applied external to a surface of the convertedportion 270 of the lamellar particle by various processes, such assol-gel, catalytic metal oxide deposition, physical vapor deposition,chemical vapor deposition, and atomic layer deposition. A functionalcoating 710 of a metal oxide can provide at least one of the followingproperties to the functional lamellar particle 700 including, but notlimited to porosity control, surface area adjustment, surface morphology(smooth vs rough) control, chemical diffusion barrier, water corrosionprevention, controlling solvent intake, structural strengthening, UVprotection, inhibition of photocatalysis, changing optical properties,anchoring for silane or other treatments, thermochromic effects,photochromic effects, electrochromic effects, and elemental signature.

In an aspect, the functional coating 710 can be a metal chosen from Mo,Zn, Ni, Ag, Cr, Au, Fe, and combinations thereof. The metal can beapplied external to a surface of the converted portion 270 of thelamellar particle by various processes, such as electroless andelectroplating, catalytic chemical deposition, chemical vapordeposition, sputtering, and vacuum evaporation. A functional coating 710of a metal can provide at least one of the following properties to thefunctional lamellar particle 700 including, but not limited to changingoptical, electrical, or magnetic properties, thermal conductivity,elemental signature, and antibacterial.

In an aspect, the functional coating 710 can be a taggant chosen fromquantum dots, inorganic and organic fluorescent and phosphorescentmaterials (organic dyes, lanthanides-containing nano-particles andlayers), microstructures, and combinations thereof. The taggant can beapplied external to a surface of the converted portion 270 of thelamellar particle by various processes, such as incorporation intopolymers, molecular bonding, and sol-gel deposition. A functionalcoating 710 of a taggant can provide at least one of the followingproperties to the functional lamellar particle 700 including, but notlimited to covert security, and elemental signatures.

In an aspect, the functional coating 710 can be a surfactant chosen fromdetergents, amphoterics, anionic, nonionic, cationic, surface activepolymers, PEG, saponin, tridecafluorooctyltriethoxysilane+tetramethylammonium hydroxide, and combinations thereof. The surfactant can beapplied external to a surface of the converted portion 270 of thelamellar particle by various processes, such as by a chemical bath or atumbling bed. A functional coating 710 of a surfactant can provide atleast one of the following properties to the functional lamellarparticle 700 including, but not limited to surface tension control,wetting and dispersion, hydrophobicity, hydrophilicity, and leafing.

In an aspect, the functional coating 710 can be a steric stabilizerchosen from polyethylene oxide, beta-diketones, carbonic acids,carboxylates, amines, tetraalkylammonium compounds, organophosphorouscompounds, silanes (e.g. methacryloxypropyltrimethoxysilane), long-chainalkyl/aryl alcohols (octanol, stearyl alcohol, benzyl alcohol), polymerencapsulation (adsorption or entanglement), PEG-methacrylate plusethylhexyl methacrylate (branched better than linear),tetra-n-octylammonium bromide, and combinations thereof. The stericstabilizer can be applied external to a surface of the converted portion270 of the lamellar particle by various processes, such as by a chemicalbath or a tumbling bed. A functional coating 710 of a steric stabilizercan provide dispersion control.

In an aspect, the functional coating 710 can be ormosil chosen fromPDMS-SiO₂, VTES-TEOS-acrylate, and combinations thereof. The ormosil canbe applied external to a surface of the converted portion 270 of thelamellar particle by various processes, such as by a chemical bath or atumbling bed. A functional coating 710 of ormosil can provide at leastone of the following properties to the functional lamellar particle 700including, but not limited to water corrosion prevention, chemicaldiffusion barrier, and mechanical protection.

In an aspect, the functional coating 710 can be an organic compoundchosen from fatty acids, diethylene glycol, Dynasylan® 1146 (adiaminofunctional silane), 3-aminopropyltriethoxysilane,tridecafluorooctyltriethoxysilane, 2-perfluorooctanoate ethyltrimethoxysilane, octadecyldimethyl trimethylsilylammonium chloride, andcombinations thereof. The organic compound can be applied external to asurface of the converted portion 270 of the lamellar particle by variousprocesses, such as by a chemical bath or a tumbling bed. A functionalcoating 710 of an organic compound can provide at least one of thefollowing properties to the functional lamellar particle 700 including,but not limited to dispersion, leafing, medium compatibility, adjustingsurface energy, hydrophobicity/hydrophilicity control, adhesion to paintbinders, and antistatic.

In an aspect, the functional coating 710 can be a polymer chosen frommonomers, oligomers, polymers, and combinations thereof. The polymer canbe applied external to a surface of the converted portion 270 of thelamellar particle by various processes, such as by a chemical bath or atumbling bed. A functional coating 710 of a polymer can provide at leastone of the following properties to the functional lamellar particle 700including, but not limited to chemical diffusion barrier, opticalproperties, carrier medium, anchor layer, mechanical strength,controlling shearing properties.

In an aspect, the functional coating 710 can be a dye chosen fromphthalocyanines, porphyrins, and combinations thereof. The dye can beapplied external to a surface of the converted portion 270 of thelamellar particle by various processes, such as by a polymer coating ora silica encapsulation. A functional coating 710 of a dye can provide atleast one of the following properties to the functional lamellarparticle 700 including, but not limited to optical properties.

In an aspect, the functional coating 710 can be a UV absorber chosenfrom titania, zinc oxide, ceria, zinc oxide bonded to 4-methoxycinnamicacid and oleic acid, TINOSORB® S (bis-ethylhexyloxyphenol methoxyphenyltriazine), TINOSORB® M (bisoctrizole), UVINUL® A Plus (diethylaminohydroxybenzoyl hexyl benzoate), UVASORB® HEB (iscotrizinol), UVINOLT150(ethylhexyl triazone), hydroxyphenyltriazines, and combinations thereof.The UV absorber can be applied external to a surface of the convertedportion 270 of the lamellar particle by various processes, such as by asol-gel or a chemical bath. A functional coating 710 of a UV absorbercan provide at least one of the following properties to the functionallamellar particle 700 including, but not limited to UV protection.

In an aspect, the functional coating 710 can be an antioxidant, such asa hindered amine light stabilizer, chosen from2,2,6,6-tetramethylpiperidine and derivatives, and combinations thereof.The antioxidant can be applied external to a surface of the convertedportion 270 of the lamellar particle by various processes, such as by achemical bath. A functional coating 710 of an antioxidant can provide atleast one of the following properties to the functional lamellarparticle 700 including, but not limited to UV protection.

In an aspect, the functional coating 710 can be a layer heat-treated inair, nitrogen, inert gas, a vacuum anneal, and combinations thereof. Afunctional coating 710 of a layer heat-treated can provide at least oneof the following properties to the functional lamellar particle 700including, but not limited to porosity control, surface area adjustment,and surface morphology control.

EXAMPLE 1

Pre-conversion lamellar particles were purchased from Crescent Bronze(Oshkosh, Wis.) as a commercial product called Brilliant Copper 104.These pre-conversion lamellar particles were made solely of copper. Thecopper pre-conversion lamellar particles had a width of about 12 micronsand a physical thickness of about 0.2 to 0.6 microns. Five grams of thecopper pre-conversion lamellar particles were introduced into a 250 mlchemical bath having a temperature of approximately 50° C. forapproximately 60 minutes. The chemical bath included (NH₄)₂CO₃/K₂S in a2:5 ratio +1% MBT(2-Mercaptobenzothaizole), CAS #140-30-4, fromSigma-Aldrich) 8% total solids concentration was present. The treatedcopper particles (e.g., converted lamellar particles) were then removedfrom the chemical bath and analyzed. The converted lamellar particlesappeared black in color and had a reflectance in a visible range of lessthan 5 percent and an L*a*b* color space (L*) value of less than 24. Inparticular, this sample had an L* less than 20 and reflectance of lessthan 4 percent. A photograph of the copper pre-conversion lamellarparticles and the converted pre-conversion lamellar particles is shownin FIG. 17. The analysis of the pre-conversion lamellar particles,surface conversion (partially treated particles), and the fullconversion (fully treated particles) is shown in Table 1 below and inthe graphs shown in FIGS. 18 and 19.

TABLE 1 Metal maximum % R 69.4 @ 700 nm color: metal L* 70.5 pre-flakeSurface maximum % R 3.3 @ 700 nm color: black L* 19.9 conversion Fullmaximum % R 3.2 @ 400 nm color: black L* 19.9 conversion

EXAMPLE 2

Silver pre-conversion lamellar particles were purchased from AMESGoldsmith, South Glen Falls, N.Y. 12803. The silver pre-conversionlamellar particles product form AMES Goldsmith was an electronic gradeproduct MB-499. It had a width of about 10 microns and thickness rangingfrom about 0.1-0.6 microns. Three sets of 1 gram silver pre-conversionlamellar particles were introduced into three sets of 100 ml chemicalbath at room temperature for approximately 7 min, 30 min., and 45 min.respectively. Each of the chemical baths included (NH₄)₂CO₃/K₂S in a 2:5ratio +1% MBT (2-Mercaptobenzothiazole). 3.5% total solids concentrationwas present. The converted silver lamellar particles were then removedfrom the chemical bath and were analyzed. Each set of converted silverlamellar particles appeared as a different color. The reflection valuesat different wavelengths in visible range were color dependent at L*>35.

The analysis of the three sets of converted silver lamellar particles isshown in Table 2 below and in the graphs shown in FIGS. 20 and 21.

TABLE 2 Metal pre-flake color: metal Maximum % R 68.7 @ 700 nm Minimum %R 59.8 @ 400 nm L* 85.3  7 min exposure color: (brown) red Maximum % R19.5 @ 700 nm Minimum % R 7.5 @ 504 nm L* 37.9 30 min exposure color:blue green Maximum % R 12.6 @ 491 nm Minimum % R 7.1 @ 666 nm L* 38.5 45min exposure color: light green Maximum % R 15.9 @ 526 nm Minimum % R9.8 @ 700 nm L* 45.2

While principles of the present disclosure are described herein withreference to illustrative embodiments for particular applications, itshould be understood that the disclosure is not limited thereto. Thosehaving ordinary skill in the art and access to the teachings providedherein will recognize additional modifications, applications,embodiments, and substitution of equivalents all fall within the scopeof the embodiments described herein. Accordingly, the disclosure is notto be considered as limited by the foregoing description.

We claim:
 1. A functional lamellar particle, comprising: an unconvertedportion of the lamellar particle, wherein the unconverted portionincludes copper or silver; a converted portion of the lamellar particledisposed external to a surface of the unconverted portion, wherein theconverted portion includes a chemical compound of copper or silver, andwherein the converted portion has a reflectance in a visible range ofless than 19.5 percent, a color different from a color of theunconverted portion, and a lightness of less than 45.2; and a functionalcoating disposed external to a surface of the converted portion; whereinthe functional lamellar particle has a width ranging from 10 microns to50 microns and a thickness of 0.1 to 2 microns.
 2. The functionallamellar particle of claim 1, wherein the functional coating can be alayer of a metal oxide; a metal; a taggant; a surfactant; a stericstabilizer; ormosil; organic compounds; polymer; dyes; UV absorbers;antioxidants; heat treatments; and combinations thereof.
 3. Thefunctional lamellar particle of claim 2, wherein the functional coatingis a layer of a metal oxide chosen from SiO₂, Al₂O₃, TiO₂, ZnO, Nb₂O₃,B₂O₃, WO₃, AgCl-doped SiO₂, Y₂O₃-stabilized ZrO₂, indium tin oxide, VO₂and combinations thereof.
 4. The functional lamellar particle of claim2, wherein the functional coating is a layer of a metal chosen from Mo,Zn, Ni, Ag, Cr, Au, Fe, and combinations thereof.
 5. The functionallamellar particle of claim 2, wherein the functional coating is a layerof a taggant chosen from quantum dots, inorganic fluorescent materials,inorganic phosphorescent materials, organic fluorescent materials,organic phosphorescent materials, microstructures, and combinationsthereof.
 6. The functional lamellar particle of claim 2, wherein thefunctional coating is a layer of a surfactant chosen from detergents,amphoterics, anionic, surfactants, nonionic surfactants, cationicsurfactants, surface active polymers, polyethylene glycol, saponin,tridecafluorooctyltriethoxysilane+tetramethyl ammonium hydroxide, andcombinations thereof.
 7. The functional lamellar particle of claim 2,wherein the functional coating is a layer of a steric stabilizer chosenfrom polyethylene oxide, beta-diketones, carbonic acids, carboxylates,amines, tetraalkylammonium compounds, organophosphorous compounds,silanes, long-chain alkyl/aryl alcohols, polymer encapsulation,PEG-methacrylate plus ethylhexyl methacrylate, tetra-n-octylammoniumbromide, and combinations thereof.
 8. The functional lamellar particleof claim 2, wherein the functional coating is a layer of ormosil chosenfrom PDMS-SiO2, VTES-TEOS-acrylate, and combinations thereof.
 9. Thefunctional lamellar particle of claim 2, wherein the functional coatingis a layer of organic compound chosen from fatty acids, diethyleneglycol, a diaminofuncttional silane, 3-aminopropyltriethoxysilane,tridecafluorooctyltriethoxysilane, 2-perfluorooctanoate ethyltrimethoxysilane, octadecyldimethyl trimethylsilylammonium chloride, andcombinations thereof.
 10. The functional lamellar particle of claim 2,wherein the functional coating is a layer of polymer.
 11. The functionallamellar particle of claim 2, wherein the functional coating is a layerof a dye chosen from phthalocyanines, porphyrins, and combinationsthereof.
 12. The functional lamellar particle of claim 2, wherein thefunctional coating is a layer of a UV absorber chosen from titania, zincoxide, ceria, zinc oxide bonded to 4-methoxycinnamic acid and oleicacid, bis-ethylhexyloxyphenol methoxyphenyl triazine, bisoctrizole,diethylamino hydroxybenzoyl hexyl benzoate, iscotrizinol, ethylhexyltriazone, hydroxyphenyltriazines, and combinations thereof.
 13. Thefunctional lamellar particle of claim 2, wherein the functional coatingis a layer of an antioxidant chosen from a hindered amine lightstabilizer.
 14. The functional lamellar particle of claim 2, wherein thefunctional coating is a layer heat-treated in air, nitrogen, inert gas,a vacuum anneal, and combinations thereof.
 15. A metallic effect pigmentcomprising a plurality of the functional lamellar particles of claim 1.16. A magnetic pigment comprising a plurality of the functional lamellarparticles of claim
 1. 17. An EMI attenuating pigment comprising aplurality of the functional lamellar particles of claim
 1. 18. Anelectrically conductive pigment comprising a plurality of the functionallamellar particles of claim
 1. 19. A heat conducting pigment comprisinga plurality of the functional lamellar particles of claim 1.